Field of the Invention
The present techniques relate to a Group III nitride semiconductor light-emitting device and a production method therefor.
Background Art
In the semiconductor light-emitting device, electrons and holes are recombined in the well layer of the light-emitting layer to emit light. To improve emission efficiency, the concentrations of electrons and holes in the well layer are preferably increased.
Therefore, the techniques to efficiently inject holes into the light-emitting layer have been developed. For example, Japanese Patent Application Laid-Open (kokai) No. 2014-027240 discloses a semiconductor light-emitting device in which the bandgap energy of the first portion 41 of the second intermediate layer 46 on the light-emitting layer 30 side is less than the bandgap energy of the second portion 42 of the second intermediate layer 46 on the p-type semiconductor layer 20 side (paragraph [0028]). Thereby, the injection efficiency of carriers into the light-emitting layer 30 increases (paragraph [0030]).
In a deep ultraviolet light-emitting device, generally, the concentration of holes is low. For example, the concentration of holes in p-type AlGaN is extremely low. Therefore, electrons may overflow from the light-emitting layer to the semiconductor layer adjacent to the light-emitting layer. As a result, the carriers existing in the light-emitting layer decease. This causes the decrease of emission efficiency. Therefore, the overflow of electrons is preferably suppressed.